Backups in sharded clusters¶
For PBM v1.0 (only)
Before running pbm backup on a cluster, stop the balancer.
In sharded clusters, one of the pbm-agent processes for every shard and the config server replica set writes backup snapshots into the remote backup storage directly. For logical backups, pbm-agents
also write oplog slices. To learn more about oplog slicing, see Point-in-Time Recovery.
The mongos
nodes are not involved in the backup process.
The following diagram illustrates the backup flow.
Important
If you reshard a collection in MongoDB 5.0 and higher versions or unshard a collection in MongoDB 8.0 and higher versions, make a fresh backup to prevent data inconsistency and restore failure.
Created: April 11, 2025